Hitherto curved glass sheet having various shapes and curvatures has been used as a window glass for an automotive vehicle. Such a window glass is produced by heating a glass sheet at a temperature of 650° C. to 700° C. near a softening point in a heating furnace, and then by pressing the heated glass sheet on a glass forming surface of a mold.
As a bending system for glass sheet, the following system has been known: For example, like a conventional example as shown in FIG. 6, a flat glass sheet cast in a heating furnace 10 is heated while being conveyed by a glass conveying bed 11 constituted of a roller conveyer or the like, in which the glass sheet undergoes a preliminarily bending at a preliminarily bending station 12; Next, the glass sheet is conveyed to a position immediately below a mold 22 at a press bending station 20 outside the heating furnace, upon which the glass sheet is lifted by a press ring 24 disposed under the glass sheet so as to be pressed on a glass forming surface 23 of the mold 22, thereby allowing the glass sheet to be bent into a desired shape; Then, the bent glass sheet is conveyed to a cooling station 30 to be cooled thereby obtaining a glass sheet having a desired bending shape (see Patent Citation 1).
In the glass sheet bending system of the conventional example as shown in FIG. 6, when the glass sheet transferred from the heating furnace 10 is bent at the press bending station 20, the glass sheet is once put on a glass mounting bed 21 disposed immediately below the mold 22. The glass mounting bed 21 is constituted of a roller 40 including wide rollers 41 and narrow wheels 42, disposed inside the frame of a press ring 24 to rotate in a conveyance direction of the glass sheet as viewed from above as shown in FIG. 9.